The present invention relates to a method of producing an organic fertilizer by utilizing fish, particularly heads of fish such as bonitoes and others as raw material.
A fish, particularly the head of fish, contains organic nitrogen (amino acids such as lysine, asparagine, glutamine, sertine, tyrosine, proline and the like), nucleic acid, organic acid, vitamins, sugars and the like. Such effective components have delayed or immediate fertilizing effect.
However, the conventional technique has utilized a fish soluble as adsorption fertilizer, but there is no method of taking fertilizing components from the head of fish and using them as a fertilizer because the removal of unnecessary components from a stock obtained by boiling fish is very difficult to do.
There are further reasons: the head of fish such as bonito and others contains a relatively great amount of crude fat and the like preventing the fertilizing component from absorbing into a plant, and an intermediate treated liquid or stock is viscous and difficult to handle.
Hitherto, applicants invented a method for producing organic fertilizer by taking fertilizing components out of fish rather than utilizing a fish soluble as disclosed in JP-A1 No. 63-260885. In this method, the whole fish body is directly crashed and then milled by means of a crasher and a mill with supplied water and subsequently digested with enzyme in a digesting tank, thereafter treated by means of separators and filter to form an organic fertilizer.